C0727Trailer Connector Circuit Malfunction
- Generic OBD-II code · Chassis
- How the car detects it
- C0727 has no public trace in the public J2012 tables, NHTSA bulletins or maker indexes, and trailer faults usually sit in B or U codes. The circuits behind the title are documented. GM trucks with the trailering app have a trailer lighting module that powers the socket with pulse-width signals; in 2019 the park, stop and turn circuits had to draw at least 55 mA before a trailer was recognised, and the module watches for bulb outage and overcurrent. Trailers with their own lighting module can confuse it. Ford traced false trailer connected messages on the 2019-20 Ranger to moisture in the 4-pin and 7-way connectors, and Stellantis advises packing the Ram 2500 bumper socket with dielectric grease against corrosion. Lamps on the trailer then fail or flicker.
- What you may notice
- Trailer lamps inoperative or flickering
- Trailer connected/disconnected message without reason
- Likely causes
- LikelyMoisture or corrosion in the vehicle trailer socket
- PossibleShort, LED load too low or own lighting module on the trailer
- RareDamaged vehicle harness or trailer lighting module
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.